Apparatus for dynamically gaging relay contacts



Dec. 8, 1959 R. A. KRAA-Y 2,916,692

APPARATUS FOR DYNAMICALLY GAGING RELAY CONTACTS Filed June 5, 19 57 gun 'm'rzwroe 57%? Y 4775 ems? United States Patent'O APPARATUS FOR DYNAMICALLY GAGING RELAY CONTACTS Robert A. Kraay, Watertown, Mass., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application June 5, 1957, Serial No. 663,824

7 Claims. (Cl. 324-28) This invention relates to apparatus for dynamically gaging relay contacts and more particularly to an apparatus for visually indicating the sequence in which pairs of contacts open or close in a multiple contact relay upon energization of the coil.

In many applicatons of multiple contact relays in control circuits, it is frequently desirable that all. pairs of contacts make or break simultaneously; or as nearly so as possible. In other applications, it may be desirable that certain contacts make before others break or that certain contacts make or break in a predetermined sequence rather than simultaneously. However, it is diflicult to achieve a verification of these conditions because observation of the operation of the relay alone will not indicate which, if any, of the contact pairs, is closing sooner or later than the remaining pairs. This is due to the small size of the contacts and the limited distance through which they travel. In order to accurately determine the operating sequence of a plurality of pairs of relay contacts, it is necessary to electrically detect this sequence.

It is therefore a primary object of this invention to provide an electro-mechanical apparatus which will detect the operating sequence of a plurality of pairs of relay contacts and convert this information into a visual indication.

It is another object of this invention to provide an optical system for translating light flashes triggered by pairs of closing relay contacts into visual intelligence indicating the operating sequence of said pairs of contacts.

It is a further object of this invention to provide an electrical circuit for flashing stroboscopic lights in accordance with the closing of pairs of contacts on a relay under test and a mirror system to reflect the light flashes upona graduated screen wherefrom the operating sequence of the pairs of contacts may be ascertained.

With these and other objects in view, the present invention contemplates a plurality of stroboscopic lights to be individually associated with pairs of contacts on a multiple contact relay, a suitable power supply, and a rotatably mounted mirror movable by the armature of the relay under test and adapted to reflect the light beams generated by the individual stroboscopic lights upon closure of the associated pair of relay contacts. Additional fixed mirrors are provided to reflect the light beams upon a glass screen coated with a fluorescent material. A plurality of scales, corresponding to pairs of contacts on the relay under test, are provided on the opposite side of the glass screen to indicate the closing sequence of the pairs of contacts in terms of percent of armature travel.

Other objects, advantages and novel features of the invention will become apparent upon consideration of the following detailed description in conjunction with the accompanying drawing wherein the single figure is a perspective view of a contact closure indicating apparatus embodying the principal features of the invention.

Referring now to the drawing, there can be seen a relay 10, which is the relay under test, energized by a battery r. CC

11 upon closure of a switch 12. The relay 10 is provided with normally open contacts 14, 15 and 16, which, together with a group of associated stroboscopic lights 18, 19 and 20, respectively, are connected to form three electrical paths through associated batteries 21 and capacitors 22. A gang switch 23 is connected across the capacitors 22 to provide a means of discharging them when this is desirable. Although the lights 18, 19 and 20 have been referred to as stroboscopic lights, it is to be understood that any type of light may be utilized which is capable of flashing briefly upon being energized.

A mirror 24 is fixed to a shaft 25 which is rotatable in a pair of bearings 26 and is positioned so as to intercept light beams emanating from the lights 18, 19 and 20. An actuating lever 28 is secured to the shaft 25 and is urged, by a spring 29, against an armature 30 of the relay 10.

An arrangement of mirror groups 32, 33 and 34 are provided to transmit the light beams reflected from mirror 24 to a glass screen 36. The side of the screen 36 upon which the light beams impinge is coated with a material which will fluoresce when subjected to bombardment by visible light. The opposite side of the screen 66 is marked with scales 38, 39 and 40 which are positioned to intercept reflected light beams which emanated from lights 18, 19 and 20, respectively. These scales are graduated in percent of armature travel. A greater or lesser number of mirror groups such as 32, 33 and 34 may be utilized; the number being determined by the accuracy desired since a larger number of mirror groups has the effect of expanding scales 38, 39 and 40 and hence increasing the accuracy.

Operation In order that a better understanding of the invention may be had, its mode of operation will now be described. The relay 10 is first secured to the apparatus in any suitable manner with the armature 30 thereof engaging the extre'mity of the actuating lever 28 as shown in the drawing. The battery 11 is then connected to terminals of the coil of the relay 10 and the lights 18, 19 and 20, batteries 21 and capacitors 22 are connected to the normally open. contacts 14, 15 and 16, as shown.

The relay 10 is then energized by closure of switch 12 which causes the armature 30 to move in the direction in dicated by the arrow. The armature 30 moves the actuat ing lever 23, against the urging of the spring 29, and thus causes the shaft 25 to pivot in bearings 26. The amount of angular displacement of the mirror 24 at any instant is, of course, proportional to the distance traveled by the relay armature.

As the armature 30 moves in the direction indicated by the arrow, it closes the normally vopen contacts 14, 15 and 16. As each of these contacts closes, current flows in the associated circuit for a brief period until the battery 21 has fully charged the capacitor 22. This substantially instantaneous current pulses the associated stroboscopic light and an instantaneous beam of light is transmitted toward the mirror 24. The light beams are then reflected from the mirrors 24, 32, 3'3 and 34 to the fluorescent coatthereon.

the corresponding mark 42 will appear. The gang switch 23 is then closed to discharge the capacitors 22 in preparation for the next operation of the device.

Using the information which appears on the screen 36,,

the movable contacts may then be adjusted to align the marks 42 so that all of the pairs of contacts are operating in the desired sequence. When it is desired that certain contacts should make before others break and vice versa, then an overlay may be provided to blank out portions of the scales 38, 39 and 40 and indicate the limits within which the contacts are to be adjusted. The relay may be sequentially actuated by any suitable pulsing mechanism to provide a continuous indication upon the screen 36 if a single actuation does not cause the spots 42 to fluoresce for a sufficient length of time to permit accurate observation.

The disclosed apparatus is readily adaptable to the gaging of relays with normally closed contacts by starting the test with the relay under test in an energized condition in which state the normally closed contacts would be held open. The relay would then be de-energized and marks 42 would be produced as before when each pair of contacts closed. These marks 42 would then be indications of the points at which the contacts open when the relay is energized and the movable contacts could be adjusted as before. To gage a relay which is provided with both normally open and normally closed contacts, a combination of the above procedures would of course be used. The marks 42 would then be indications of the points at which the contacts either opened or closed, depending upon the nature of any particular pair of contacts.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. An apparatus for registering the closure sequence of pairs of contacts on a multiple contact relay comprising means for creating instantaneous beams of light in response to the closure of pairs of contacts, and means for translating said beams of light into visual indications of the sequence in which the individual pairs of contacts closed.

2. In an apparatus for indicating closure of contacts in a relay, a display screen, means for energizing the relay, light means connected to said contacts for producing a flash of light upon closure of each contact, and means for projecting each flash of light onto the display screen.

3. A detecting and indicating apparatus for determining the closing sequence of pairs of contacts on a multiple contact relay comprising a plurality of light sources, electrical means connecting each pair of relay contacts to a light source for pulsing each light source upon closure of the associated pair of contacts to cause each light to emit an instantaneous beam of light, means for energizing the relay to close the contacts, and means for translating said beams of light into visual intelligence.

4. A detecting and indicating apparatus for determin ing the operating sequence of pairs of contacts on a multiple contact relay comprising means for creating instantaneous beams of light in response to the closure of pairs of contacts, means for energizing the relay to close the contacts, and an optical system for projecting said beams of light upon a screen to indicate the operating sequence of the various pairs of contacts.

5. An apparatus for detecting and indicating the sequence of closure of a plurality of pairs of contacts in a multiple contact relay comprising a plurality of light sources, electrical means interconnecting said light sources and said contacts for pulsing each light source in accordance with the closing sequence of said pairs of contacts to cause said light source to emit an instantaneous beam of light, a mirror rotated by movement of an armature of said relay for reflecting said beams in varying directions determined by the times at which the pairs of contacts close, and a calibrated fluorescent screen positioned to intercept the reflected beams for indicating the sequence in which the pairs of contacts closed.

6. In an apparatus for indicating time of closure of a plurality of contacts associated with a relay coil, means for energizing the relay coil to close the contacts, a plurality of light sources sequentially operated in accordance with the closure of the contacts, a display screen, means for reflecting light from said sources onto the screen, said reflecting means including a rotatably mounted reflector, and means actuated by the energization of the relay coil for rotating the reflector.

7. An apparatus for detecting and indicating the sequence of closure of a plurality of pairs of contacts in a multiple contact relay comprising a plurality of stroboscopic lights, a plurality of batteries and capacitors, one each of said batteries and capacitors being connected in series with one of said stroboscopic lights through one pair of contacts on the relay, means for energizing the relay to close the contacts whereby the charging current for each capacitor pulses the associated stroboscopic light to produce an instantaneous beam of light, a mirror rotated by movement of the armature of the relay for reflecting said beams in varying directions determined by the times at which the pairs of contacts close, and a calibrated fluorescent screen positioned to intercept the reflected beams for indicating the sequence in which the pairs of contacts closed.

References Cited in the file of this patent UNITED STATES PATENTS 2,712,640 Mork et a1 July 5, 1955 2,805,388 Brown Sept. 3, 1957 FOREIGN PATENTS 81,262 Norway Jan. 12, 1953 

